The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection.Significant contributions from both the BornOppenheimer(BO)forbidden reaction F^(*)(^(2)P_(1/2))+HD→DF+H and the BO-allowed reaction F(^(2)P_(3/2))+HD→DF+H were observed.In the backward scattering direction,the contribution from the BO-forbidden reaction F^(*)(^(2)P_(1/2))+HD was found to be considerably greater than the BO-allowed reaction F(^(2)P_(3/2))+HD,indicating the non-adiabatic effects play an important role in the dynamics of the title reaction at low collision energies.Collision-energy dependence of differential cross sections(DCSs)in the backward scattering direction was found to be monotonously decreased as the collision energy decreases,which does not support the existence of resonance states in this energy range.DCSs of both BO-allowed and BO-forbidden reactions were measured at seven collision energies from 3.03 meV to 17.97 meV.It is quite unexpected that the angular distribution gradually shifts from backward to sideway as the collision energy decreases from 17.97 meV to 3.03 meV,suggesting some unknown mechanisms may exist at low collision energies.
Heilong WangYu LiZhirun JiaoHongtao ZhangChunlei XiaoXueming Yang
Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine initial quantum state selection,employing a hexapole inhomogeneous electric field,with quantum state resolved detection,using(1+1')resonantly enhanced multiphoton ionization and velocity map ion imaging.The differential cross sections and polarization dependent differential cross sections are shown to agree well with quantum mechanical scattering calculations performed on ab initio potential energy surfaces[J.Klos et al.J.Chem.Phys.137,014312(2012)].By comparison with quasi-classical trajectory calculations,quantum mechanical scattering calculations on a hard-shell potential,and kinematic apse model calculations,the effects of the attractive part of the potential on the measured differential cross sections and collision-induced rotational alignment moments are assessed.
Mark BrouardHelen ChadwickSean DSGordonCornelia GHeidBalazs HornungBethan NicholsJacek KlosPablo GJambrinaFJavier Aoiz
